The field of the present invention is protective devices for light emitting bulbs. More specifically, the present invention is directed to an improved guard for a light emitting bulb.
Light sources of various types have long been a part of outdoor construction projects where work is performed at night. Quite often ordinary incandescent bulbs are employed as such a light source because of their portability and their simplicity, requiring only a power source, cable and sockets. However, incandescent bulbs suffer two significant drawbacks. First, they are very fragile. Second, they become quite hot when in use. Their fragile nature makes them quite vulnerable to the rough environment of construction projects and the like. The high temperature operation of these bulbs creates several problems. The heat can cause burns to the workers and fires. High thermal stresses are experienced when rain hits the hot bulbs causing them to shatter. Furthermore, protective devices placed about such incandescent bulbs have the problems of getting hot themselves and also trapping in the heat if not properly constructed.
To improve the utility of incandescent bulbs for rough outdoor environments such as construction projects, a wide variety of guards has become available. The guards which have been developed have generally attempted to provide four features, unimpeded light emission, high impact resistance, venting or heat dissipation, and rain protection. Of these features, venting and rain protection have been found to be somewhat conflicting in the design requirements necessary for meeting these goals. Large vents allow rain to get to the hot bulb while good rain protection reduces the venting capacity. Design of such devices with these goals in mind has been further complicated by the fact that rain is often accompanied by wind. The wind both drives the rain laterally into otherwise protected vent openings and can swing the guard and light bulb assembly from a vertical orientation. In both cases, the wind can act to promote rain water getting onto the light bulb contained within the guard, causing it to shatter.